Smart city is modern urban concept that is essential for people to have convenient life. This paper presents the purpose of smart city using IoT. the internet of things application are enabling smart city initiatives worldwide. It provides ability to monitor, control and manage devices and quick response to user . Moreover this paper also presents a comprehensive study on the smart city concept in the view of its applications in cities such as smart parking, smart streetlights ,smart garbage monitoring system, Water overflow system and many more. The goal of these applications is to bring about a sustainable and pleasant living environment for people in city utilizing IOT technologies in a smart city. Here ,IOT plays a key role in making cities smarter.